| ConsumerKey | Value class for OAuth consumer keys. |
| OAuthSignatureCalculator | Simple OAuth signature calculator that can used for constructing client signatures for accessing services that use OAuth for authorization. |
| RequestToken | Value class used for OAuth tokens (request secret, access secret); simple container with two parts, public id part ("key") and confidential ("secret") part. |
| ThreadSafeHMAC | Since cloning (of MAC instances) is not necessarily supported on all platforms (and specifically seems to fail on MacOS), let's wrap synchronization/reuse details here. |